Since ancient times gold has been highly valued as the most important precious metal and mainly used in the form of ornaments or treasures. Recently, gold has also been recognized to be effective in promoting human health and used in a pure gold health bracelet, Japanese sake containing gold leaves, and the like. However, the effectiveness of these products in health is not sufficiently recognized although they are distinguished as luxury items containing expensive pure gold. Lately, in response to health-oriented social trends, health promoting effect of gold have again attracted an attention and it has been found that the health promoting effects are more remarkable in the form of gold ions or ultrafine gold particles than in the form of simple gold or gold leaves.
Potential of gold ions and fine gold particles being effective in promoting health or healing diseases has attracted a great deal of attention and a considerable contribution of gold to health has been known (“Golden Water Cures Intractable, Serious Diseases” by Tofu Takada). Therefore, further technological development, in particular in applied utilization of an aqueous solution or aqueous dispersion of gold ions or fine gold particles, is needed. However, several problems remain to be solved in implementation of such technology.
As mentioned above, water products containing fine gold particles are also known (ditto, page 64). However, in most products, gold leaves or gold powders are simply dispersed in water. It is extremely difficult to dissolve gold ions or fine gold particles in water and dissolution methods so far available are limited to those with the use of aqua regia or gold electrolyte.
In such conventional methods, requirements in terms of production cost and economic efficiency are not satisfied and moreover, technological problems such that health-promoting function cannot be fully exhibited remain to be solved.
In order to solve these problems in conventional methods and realize the potential of gold ions and fine gold particles being effective in promoting health or healing diseases, technological development in this field might be in progress. However, only a few techniques of this field have been disclosed in patent publications that are generally known to precisely reflect the progress in technological development, which indicates that potentiality in technological development in this field is still great.
The few disclosed prior arts mentioned above include Japanese Utility Model No. 304628 in which an organic antibacterial agent, such as antibacterial gold ions immobilized onto an ion exchange group of zeolite is admixed with an polyolefin mold resin in order to provide an antibacterial tank for drinking water that can prevent unwanted bacteria from invading through the wall of the tank and avert detrimental effect caused by chemicals dissolved without spoiling the flavor of the drinking water, Japanese Patent Application Laid-open No. H9-220580 in which in order to provide mineral water containing minerals, such as gold ions, that is useful in the human body, mineral carriers are suspended in water and then the minerals are released into water by stimulation by mineral release stimulating means, such as acid addition and electrolysis; Japanese Patent Application Laid-open No. H9-10772 in which in order to produce an inexpensive bactericide, antiseptic water having excellent bactericide activity, a heavy metal such as gold is dissolved into acidic ionic water having a pH 2.6 to 4.5 produced using an electrolytic water purification system or oxidation potential water having a pH lower than 2.7; and Japanese Patent Application Laid-open No. H5-280841 in which in order to produce a health ice product having foreign matters, such as gold leaves, evenly dispersed in an ice block, gold leaves are evenly admixed with crushed granular ice while stirring, the granular ice mixed with the foreign matter is packed into an ice-making can, and water is gradually injected from the bottom of the ice-making can to form ice.
However, virtually all of these conventional techniques enclosed are far from suitable means to solve the abovementioned problems and cannot basically solve the problems, although the technique disclosed in Japanese Patent Application Laid-open No. H9-10772 is noticeable, in which in order to provide mineral water containing minerals, such as gold ions, that is useful in the human body, mineral carriers are suspended in water and then the minerals are released into water by stimulation by mineral release stimulating means, such as acid addition and electrolysis.
Utilization of activity of gold ions and fine gold particles in physiologically active materials, health food materials and pharmaceuticals is important as technology directly related to everyday life. Their application will become more frequent in future and thus the development of technology in this field is highly expected.
Accordingly, the present inventors intensively studied the process of producing health water containing ultrafine gold particles in prospect of possibility that health can be promoted in extremely simple way and various symptoms can be improved by drinking water containing gold ions or fine gold particles, and thus completed the present invention.